Electronic device



Aug. 20, 1940. I F. sc 2,212,249

ELECTRONIC DEVICE Filed Sept. 10, 1936 INVENTOR FRITZ SCH/2075A?ATTORNEY PahnteiiAug. 20, 1940 2,212,249 ELECTRONIC DEVICE FritzSchroter,

, a corpora- Application September 10, 1936, Serial No. 100,161

Germany September 12, 1935 9 Claims. (01. 178-75) This invention relatesto electronic signaling apparatus and in particular to televisionreceiving Jection of the picture.

P. Selenyi has described in Elecktrotechnishe Zeitschrii't, vol. 56, No.35, 1935, on page 961 an carrier through electron charges and subsequentcontains in the direction of movement of the in- 10 dusting with apowder such as lyco-podium powtermediate film Assuming for instance 200such der. This author furthermore has already pointed lines, it would benecessary in a line transversal to the applicability of this method tointermediate to the advance of the intermediate film to provide filmtelevision reception To this end, the image 200 independent stationaryrecording systems opmade visible through dusting on a transparent orerating simultaneously, past which the film moves l5 reflecting carrieris recreated on the recelving continuously andin synchronism with therespecscreen at high enlargement by way of diascopic tive photo-electricevaluation at the transmitter, or epidiascopic projection. in orderlater to be projected on the receiving One 01' the objects of myinvention is to pro screen following the dusting 1n step-like fashionvide n mp ved in rm a film type of tele- (Maltese cross) or incontinuous running (by 20 11 System of the kind p opo e by Sel nyl. theuse of an image balancing arrangement for Another object 01 my inventionis to provide instance Wehlers prism wheel, mirror arrangea television aparatus which shall have increased ment according to Mechau). At thetransmitter resolution by supplying a substantial increase in therefore,200 separate photocells or photo-elethe number of elemental areasrepresentative of ments with the same number 01' adjoining am- 5 thepicture surface. pllfler channels are required or else in place Afurther object 01' my invention is to provide thereo a transformationarrangement which disa simplified intermediate fllm projectiontelevitributes the image modulation gained in the S111- sion receiverwhich shall be easy to operate and gle channel method, true to the imagepoints over have comparatively low initial cost as well as low 200channels. so maintenance cost. It in view 01 the structural diflicultiesin the Other and ancillary objects will ppear upon atore-describedmultiple arrangement the numconsideration of the specification taken inconber of the simultaneously acting transmission j n ti n wi h the rawng, in which: channels would be made smaller than the number Fi 1 showsone embodiment of my invention; of divisions along the one or the otherimage co- 35 Fig. 2 shows an electrode structure used in the ordinate, ie smaller than the number of lines embodiment shown in Fig. 1;appertaining to the dimension under considerai 3 h w a ir it scheme: andtion, there arises the necessity of a rapid relative 4 S fiWS fl e odimnt of my invenmovement of the intermediate nlm to the recordtion. ingmeans In view of the apparent mechanical 4n B l nyih s po nted out thath s dusting method dimeulties of such a method this invention enwouldpermit the recording of images up to visages the application of movingmodulated 10 em n areas D nd- Since the cathode rays for the imageproductmn whereby order of the number of elemental areas in the thesecathode rays produced in the vacuum act im 1 68 od y r y t 50 000 and mre f directly or indirectly in the free space in order o definition theecording according there to produce on the carrier of the image toSelenyi's method would be exceeded at 124 record the locally varyingelectron charge, over images per second This drawback is now overwhichthe fine particles are dusted. come in accordance with this invention bymeans Hereby the intensity control of the cathode ray of parallelconnection of several transmission through the transmitted imagemodulationaswell channels in conjunction with storage and amplifi= asthe deflection in accordance with one of the two image coordinates takesplace in the ordinary way in the cathode ray tube proper.

Figure 1 shows a mode of structure according to the invention relatingto a special construction 5 a of the grid-controlled electronicrecording: system.

Between the anode plate I and the grid 3 of slotlike construction, thereis moved the record carrier which is a transparent, highly insulatingfilm free of emulsion, whereafter it passes through the dusting andprojection zone. The film 2 suitably forms an endless loop of sufilcientlength in whose circular path in back of the projection zone a devicefor wiping oil the dusted powder is inserted. In parallel to the gridslot 3, an indirectly heated cathode is arranged consisting of a tubularceramic body whose bore contains a heating helix 5. This incandescentcathode whose length corresponds to the image line to be traced on thefilm 2, instead of having a smooth surface has a roughened surfaceprovided thereon such as shown greatly enlarged in Figure 2 as part ofthe longitudinal section through 4. The cathode may for example consistof alternate rings of metal separated by smaller diameter insulators togive the raised surfaces 9, Hi, II which are covered with a conductingmaterial and separated from each other by insulating intermediatespaces. In this manner the cathode is subdivided into a plurality ofelectrically independent emission zones corresponding to the line.According to Figure 1 and Figure 3 these emission zones are connectedacross conducting leads to a corresponding number of contacts 6 arrangedin the interior of the cathode ray tube 8. The connections are insertedthrough and held by the glass wall. They come in contact in successionwith the cathode ray i modulated and moving along the line and producedin the tube 8, and these connection lines owing to suitable preparationof their surfaces are charged negatively. The lycopodium powder 43 inthe sieve 4! may then be dusted over the insulating medium.

In Figure 3 there is shown the circuit scheme. The cathode 4 shown inenlarged cross section is provided with an oxide layer l2 emittingelectrons said layer being disposed on the side facing the grid 3 orslot shaped orifice 3' of the grid and also facing the film 2. The oxidecovers the metallic carrier ring surrounding the entire circumference ofthe cathode and which is in connection with a constant current source atthe inner contact 6 of the cathode ray tube 8 as well as across theresistor [4. Element l3 designates an anode with slot-shaped orificeprovided in the cathode ray tube, and in back of which the line of thecontacts 6 is arranged. The potential of the current source connectedwith l2 across it is slightly more positive than that at which grid 3 ismaintained constant. Consequently, in the absence of the cathode ray,the grid 3 produces a blocking effect across the entire length of thecathode 4, so that no electrons can arrive at the film 2. If however,the modulated cathode ray 1 moved along the line of the contacts 6supplies the cathode elements with less negative charge. The field ofthe anode l grips in a corresponding degree through upon the chargedemission zones of the cathode 4 and from there is caused a transit ofelectrons to the carrier of the record 2, which transit is controlled inaccordance with quantity of charge. The emission of each cathode elementinto a region of negative potential relative to the grid by properchoice of the radiation conditions, of the size of the resistor l4 andof the capacity of the charged part, continues up to the time at whichthe cathode ray returns to the same place, i. e., it last approximatelythroughout the du ation of an image line.

Since during this time the film 2 has advanced by the width of an imageline, there will be obtained on the carrier 2 a suflicient spacialelectron charge, so that it is possible to produce charges on the filmeven in case of a very large number of image points. The recordingfrequency becomes equal to the image line frequency, and hence isessentially reduced as compared with the image point frequency. It isalso possible to modify this method; thus instead of subdividing thecathode 4 in Figure 1, to subdivide the grid 3 and to connect itselements with the contact line 6 in the ray tube. In this case apositive or negative image record would be obtained in accordance as towhether the ray 1 at the electrodes 6 has a factor of the secondaryemission that is greater or smaller than 2. However, in this case itwould be difilcult to eliminate the errors caused by the control of thecontact potential at the individual elements of the grid and by thevarying activation thereof.

Figure 4 shows another embodiment of the invention. Element i againsignifies an anode arranged in back of the film 2 as seen from the sideof the cathode ray, and which is maintained at a still higher positivepotential than the last acceleration anode in the cathode ray tubeproper. The tube 8 is designed as Lenard tube, thus containing a window4 for the exit of the cathode ray, and consisting of a thin foil oflight metal. If beryllium is chosen for said foil the passage of theelectron ray into the open can already be achieved with an accelerationpotential of about 20,000 volts. If the film 2 is placed closely infront of the Lenard window 4, and if the field between 4 and I stillproduces a highly accelerating action upon the electrons passing intothe open, there can be obtained on 2 a very high electron chargefluctuating along the image line with the variation in the brightness.The carrier of the foil 6 is a metal piece 3 fused to the glass tube 8in accordance with a known method, and which has a hollow space forcirculating cooling water. 7

Element l5 designates an inner conducting layer serving at the same timeas acceleration anode, l6 and H are crossed coil pairs for the magneticdeflection of the cathode ray in the direction of the image and line, Itis the first anode, I9 is the control electrode for the intensitymodulation, 20 is the shielded cathode system, and element 2| is thelead-in of the electrode connections. In order to increase the life ofthe Lenards foil under the action of the outer air pressure, it ispreferred to mount the same on a plate having a small longitudinal slot.In this case the operation would be carried out only with a single linemovement of the cathode ray along this slot, while the line alternationof the recording is effected by continuous advance of the film 2. Inthis case, it is obvious that one of the deflection coil pairs l6, I!can be dispensed with, while the image alternation is synchronized withthe advance movement of the film.

Having now described my invention, what I claim is:

1. The steps in the method of producing charges on an insulating mediumin air comprising developing a. plurality of elemental thermionicelectron emitting sources, directing the electrons emitted from thesources through air toward the insulating medium, producing a focusedbeams of electrons, and controlling the intensity of the directedelectrons in accordance with the produced beam.

2. The steps in the method of producing charges on an insulating mediumin air comprising developing a plurality of elemental thermionicelectron emitting sources, directing the electrons emitted from thesources through air toward the insulating medium, producing a focusedbeam of electrons, controlling the intensity of the produced beam andcontrolling the intensity of the directed electrons in accordance withthe produced controlled beam.

3. The steps in the method of producing charges on an insulating mediumin air comprising developing a plurality of elemental thermionicelectron emitting sources, directing the electrons emitted from thesources through air toward the insulating medium, producing a. focusedbeam of electrons, controlling the intensity of the produced beam,deflecting the controlled beam, and controlling the intensity of thedirected electrons in accordance with the deflected controlled beam.

4. The steps in the method of producing charges on an insulating mediumin air comprising developing a plurality of elemental thermionicelectron emitting sources, directing the electrons emitted from thesources through air toward the insulating medium, producing a focusedbeam of electrons, controlling the intensity of the produced beam,sequentially actuating each of the plurality of developed sources by thecontrolled beam, and controlling the intensity of the directed electronsin accordance with the actuation of the developed sources by theproduced beam.

5. The method of producing charges on an insulating medium in airrepresentative of the intensity of illumination of elemental areas of animage to be produced comprising the steps of developing a plurality ofelemental thermionic electron emitting sources, directing the electronsemitted from the sources through air toward the insulating medium,producing a focused beam 0! electrons, developing a source of electricalimpulses representative of the image to be produced, controlling theintensity of the produced beam in accordance with the developedelectrical impulses, and controlling the intensity of the directedelectrons in accordance with intensity of the controlled produced beam.

6. The method of producing a record on an insulating medium in airrepresentative of an electrically transmitted image which comprises itthe steps of developing a plurality of elemental thermionic electronemitting sources, directing the electrons emitted from the sourcesthrough air toward the insulating medium, producing a focused beam ofelectrons, developing a source of electrical impulses representative ofthe image to be produced, controlling the intensity of the produced beamin accordance with the developed electrical impulses, controlling theintensity of the directed electrons in accordance with intensity of thecontrolled produced beam, and subsequently dusting dielectric particlesover the insulating medium.

'7. In 'combination, an insulating medium, a flat electrode, anapertured electrode, means for positioning the insulating medium betweenthe two said electrodes, a plurality of elemental thermionic electronemitting sources positioned adjacent the apertured electrode, a cathoderay tube comprising means for developing and controlling a cathode ray,and means to control the intensity of emission of electrons from theelec tron sources by the intensity of the cathode ray.

8. In combination, an insulating medium, a fiat electrode, an aperturedelectrode means for positioning the insulating medium between the twosaid electrodes, a plurality of elemental thermionic electron emittingsources positioned adjacent the apertured electrode, a cathode ray tubepositioned in register with said sources comprising means for producingand controlling a concentrated cathode ray, means to control theintensity of emission of electrons from the electron sources by theintensity of the cathode ray, and means to direct the emitted electronsthrough air upon the insulating medium.

9. In combination, an insulating medium, a flat electrode, an aperturedelectrode, means for positioning the insulating medium between the twosaid electrodes, a plurality of elemental thermionic electron emittingsources positioned adjacent the apertured electrode, a cathode ray tubepositioned in register with said sources comprising means for producingand controlling a concentrated cathode ray, a source of electricalsignalling energy, means to control the cathode ray intensity inaccordance with the electrical signals, and means to direct theelectrons emitted from the sources through air upon the insulatingmedium.

FRITZ SCIEOI'ER.

